My invention relates to a warning device for sea mammals, specifically Odontocetes, and more specifically dolphins, or whales, upon their approach to a shoal area.
My invention also provides a means to funnel or guide these animals.
It is well known that whales and dolphins utilize sonar to sense land and solid objects in the water.
What is not so well understood is the cause of the periodic stranding of whole schools of these mammals. These strandings result in needless mass deaths, injuries and significant clean-up problems.
Further strandings occur and recur at specific places such as the beachings at Eastham on 10/6/84--94 Pilot Whales; Eastham on 10/9/84--9 Pilot Whales; Kingsbury Beach on 12/6/81--12 Pilot Whales; Wellfleet on 11/16/82--68 Pilot Whales.
Inventor subscribes to the theory that sonar utilized by the herd leader returns a false report of deep water and the school finds itself stranded before it realizes what is happening. Certain beach areas characterized by a long, sloping, shallow basin are susceptible over and over again to sea mammal strandings. These areas are well known to marine biologists.
The prior art is skimpy with respect to passive sonar devices. The majority of the prior art comprises active sonar devices.
For example U.S. Pat. No. 4,488,271 relates a deep ocean wide band acoustic baffle. This device discloses a hyudracoustic transducer which provides a hemispherical radiation pattern in the desired frequency and pressure.
U.S. Pat. No. 4,546,459 discloses a method and apparatus for a phased array transducer. This again is an active hydroacoustic device.
What is needed is a passive hydracoustic device which reacts to the sonar emitted by the sea mammels to warn them off the shoal area, which makes sense economically and which does not interfere with marine surface traffic, or other forms of marine life.